It is well known and widely accepted in the petroleum refining industry to treat sour petroleum distillates with a supported metal phthalocyanine catalyst disposed as a fixed bed. The treating process is typically designed to effect the catalytic oxidation of offensive mercaptans contained in the sour petroleum distillates. Air is most often used as the oxidizing agent. The sour petroleum distillates most frequently treated are gasoline, including natural, straight-run, and cracked gasoline. Other distillates include fractions such as naphtha, kerosene, jet fuel, fuel oil, lube oil, and the like.
U.S. Pat. No. 2,853,432 discloses the use of metal phthalocyanine as the catalyst for treating sour petroleum distillates to effect the catalytic oxidation of mercaptans and other offensive sulphur-containing compounds. It is disclosed that the metal phthalocyanine may be in solution or utilized in association with a solid carrier.
U.S. Pat. No. 4,248,694 discloses a process for treating a mercaptan-containing sour petroleum distillate with a solid composite prepared by impregnating high-density activated charcoal particles with a metal phthalocyanine catalyst. This patent discloses that the impregnation from a methanol solution had been used but found objectionable due to the relative expense, toxicity, and difficulty in disposing of the methanol solution. Specifically, this patent is directed to utilizing ammonia or ammonium hydroxide as the solvent for the metal phthalocyanine catalyst when impregnating the solid composite catalyst.